I am trying to migrate my OS from an SSD to a bigger one. I ran Disk Clone. Went well. I can see from the volume on the disk that the files are there, but when I bring up that folder with File Explorer, it shows nothing.

I switched boot order, so that the bigger disk is now first, but it booted to the smaller one anyway.

So, what do I have to do to that clone to make it function as the master drive running the OS?

Try disconnecting all drives but the new cloned one and see what happens. This really should have been the first step after cloning. If still nothing, try running windows startup repair 3 times. If nothing, clean the drive through diskpart and clone again, but only have the cloned drive connected after completion.